


We've Learnt Love//Down To Our Bones

by Adel Mortescryche (Mortescryche)



Series: Poisonous Smiles Wrapped in Diaphanous White (Fem!Byakuran AU) [2]
Category: Katekyou Hitman Reborn!
Genre: Alternate Universe - Post-Canon, BAMF Uni | Yuni, BAMF everyone, Cis Female Byakuran, Don't You Mess With His Princess, Established Relationship, F/M, Fluff, Gamma's totally a Done Dad, Gen, Genderbending, Genderswap, I ship this ot3 even when Byakuran's male guys, M/M, Multi, OT3, Overprotective Parents, POV Gamma, Polyamory, Post-Canon, Rule 63, Team as Family, Tooth-Rotting Fluff, Women Being Awesome, Women are badass, fem!Byakuran, the fem!Byakuran thing is part of the series
Language: English
Status: Completed
Published: 2018-06-20
Updated: 2018-06-20
Packaged: 2019-05-26 01:29:26
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,450
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14989781
Author URL: https://archiveofourown.org/users/Mortescryche/pseuds/Adel%20Mortescryche
Summary: There are a few things you really don't want to know when you've all but become a Father to your late Boss-come-Girlfriend's daughter, who's also your current Boss. That's she's currently in a relationship with the Young Don of the Vongola Famiglia and That Dratted Megalomaniac? Is one of them.(Or: That one in which Gamma finds out that Yuni's in a relationship with Tsuna and Byakuran, and has to learn to deal. Gokudera helps, Kikyou... sort of helps, and Gamma is so tired of being the only sane adult in the room okay.)---Can be read as a standalone oneshot.





	We've Learnt Love//Down To Our Bones

The first time he caught Yuni in bed with the young Don of the Vongola, he nearly put a bullet through Sawada’s head; damn the consequences of it because _Sawada was in bed with his baby girl._

Who cared if they had their clothes on. Gamma sure as fuck didn’t.

Sawada managed to escape out the window, somehow, much to Gamma’s eternal frustration, but Yuni distracted him from actually chasing the brat down. And then he’s being pushed into the armchair by the window, with Yuni glowering cutely at him. The expression makes him slow down, if only because Yuni was beginning to look more and more like her mother the older she gets and the reality of that hasn’t really stopped hurting him yet.

“You do realize I’m getting older, right,” Yuni asked him seriously, and he grumped, crossing his arms and looking away.

Yuni slapped her hands on either side of his face, and made him turn so he was facing her head on, pouting when he scowled at her.

“Gamma,” she said, bending down a little so she could look at him directly, “I’m growing older physically, I’m the Donna of the Giglio Nero and now that I’m actually interested in pursuing someone, the people I’ve picked are actually allied with us. You don’t get to judge my choices.”

“I’m your guard and advisor, it’s all but required for me to judge your- wait, _people?”_ Gamma repeated the latter in shock.

Yuni blinked back at him, looking startled for all of a second before her expression shifted to one of innocent confusion. That Gamma didn’t trust one bit; Yuni looked _exactly_ like Aria had when she’d done something she knew Gamma wouldn’t approve of.

“Princess,” he sighed, and Yuni _giggled._

*

“Oh thank fuck, I don’t need to deal with Kikyou and Takeshi all on my own any longer,” Gokudera said fervently, when he called Sawada’s right hand to complain.

“Excuse me?” Gamma replied, confused, and Gokudera gave a sharp bark of laughter that sounded a little like Gamma felt.

“Just get your ass over to the mansion Byakuran and Yuni bought the next time you’re in Namimori, old man. I’ll save the scotch for you. Unless you want to discuss things before we head back, anyway.”

Gamma wasn’t very comforted by that, but he agreed to the offer anyway. It was better to give the situation some time to settle, instead of going to pick a fight on Vongola territory, anyway. And Gokudera was easy to get along with; he understood the pain of needing to run after a Sky that insisted on breaking the world whenever they were bored. Sawada seemed at least as bad as his little princess, judging by the memories that had been sent back to him by the Gamma in the future, but at least neither of them were as bad as-

Gokudera’s long sigh wass background music to Gamma’s pained choking when he actually registered Kikyou’s name and connected it to Byakuran. Of all people his princess had to pick, why in the world had she picked Sawada and _Byakuran._

“You’ve got to admit, at least this means no one’s going to dare messing with us, right?” Gokudera muttered, sounding ruefully amused, once Gamma stopped choking in horror.

“I think I’d rather people _did_ mess with us, at least then I’d get to work off my frustration,” Gamma groaned, burying his face in his knees. Gokudera laughed, sounding rather like he agreed with Gamma on that front.

“Has this been going on for long?” Gamma found himself asking, and Gokudera sighed again.

“Well. Juudaime and Byakuran have been seeing each other off and on since we were all in junior high. I thought _everyone_ knew that by now.” He responded, and Gamma rolled his eyes. Of _course_ everyone knew about that. As if the future memories and what Byakuran was capable of weren’t terrifying enough all on their own without finding out that the Vongola’s next Don was already in a _relationship_ with her.

“I meant with _Yuni,”_ Gamma stressed, and Gokudera coughed, sounding uncomfortable.

“I… suspected they might both be interested in her? But Juudaime’s been pretty clear on not suggesting a relationship unless Yuni approached _them,_ if I’m not mistaken.”

“That… really doesn’t make me feel any better,” Gamma admitted tiredly, and Gokudera laughed a bit more.

“You and me both, old man. You and me both. Just… stop by my apartment or something if you don’t want to confront any of the others or have to face Maman when you’re in Namimori, okay?”

“If anything, Sawada’s mother should be uncomfortable talking with _me._ Well, sure. Your apartment it is. I’ll call again later. _”_ Gamma grunted, and ignored the violent swearing that erupted from the younger man.

He honestly didn’t feel any better about the situation, but at least it sounded like Sawada was thinking things through. How much that really counted in his favor when he’d been seeing Byakuran in a romantic light since he was a teenager, even after going through the hellscape that was the world ten years later and _actually being the one to kill Byakuran in the first place,_ was debatable.

*

Even if he didn’t really feel comfortable with the situation, Gamma had to admit that he didn’t find it all that surprising that this was where things had eventually led. Yuni had always seemed oddly attached to Sawada and Byakuran, for all that the memories she had inherited should have created some dissonance in her head. Gamma inherited memories had troubled _him_ more than enough, after all. They supplied him with much needed information, but they always gave him a bit of a headache when he thought about them, as if they didn’t fit the way memories were supposed to.

His princess never seemed to have that problem, though. When the Arcobaleno trials had started, she hadn’t even hesitated to contact Byakuran to protect her – and Byakuran had responded immediately, appearing in full force to help support her. Gamma still didn’t like the young woman, he doubted he ever really would – but he couldn’t deny that she was powerful and fully on Yuni’s side, whatever her ulterior motives for that might be.

As for Sawada… Sawada was the same. Gamma understood the young Japanese Don even less than he understood Byakuran; a person with the kind of power Sawada wielded couldn’t possibly be as good natured and innocent as he seemed on the surface. Not when he’d somehow won over some of the most dangerous powers in the Cosa Nostra, and not when he’d been in bed with Byakuran Gesso for as many years as he’d been. The man refused to make any sense at all, and Gamma honestly wished his Princess had picked someone else.

The part of him that attempted to watch over Yuni as a daughter in Aria’s absence _despaired._ Surely Yuni could have pursued someone who wasn’t already in a committed relationship with another woman. She was worth so much more than simply being some kind of dalliance on the side.

Gamma would have been more infuriated if another part of him wasn’t so sure that Sawada and Byakuran _wouldn’t_ simply make sport of Yuni. He hated himself for noticing it, but he couldn’t deny that they both respected her more than that.

*

He confronted Yuni again, before their summer visit to Namimori, as usual. Gamma wondered a little despairingly if he shouldn’t have seen this shift in the relationship coming, when Sawada had been inviting Yuni to spend time in Namimori ever since she’d grown old enough that it wasn’t dangerous for her to be in transit outside of Sicily. The fact that Byakuran and her people inevitably showed up excepting the years during with Byakuran had been busy with research in her final years of graduate school, only made Gamma ore suspicious.

Yuni actually laughed in his face when he confessed his fears, though.

“You’re being silly, Gamma. I’ve always liked Tsuna and Byakuran-chan. They’re good friends. You wouldn’t ask me if I was romancing _all_ my friends, would you?”

“That argument doesn’t work when you’re _actually_ romancing Sawada and Byakuran, Princess,” he sighed back, and Yuni giggled, as cheerful as ever.

“Well, maybe. But Tsuna and Byakuran-chan have always been very happy together! I didn’t ask them if they wanted me in their relationship until my birthday this year. Tsuna was so embarrassed – but Byakuran didn’t mind sharing. And I like them both! So-”

“Gah, too much information, Princess, take some pity on me, _please.”_ Gamma all but whimpered, pressing his palms to his eyes, and Yuni breathed in sharply, before abruptly throwing her arms around his shoulders to hug him tightly.

“Thank you. For asking about it, and caring,” she whispered, and Gamma couldn’t move, his arms still trapped in place by her hug. Which was a _shame,_ because he desperately wanted to hug his girl back.

“Why wouldn’t I,” he replied instead, trying to move his hands so that he could look down into her face. “You’re my little princess. You’ll _always_ be my princess, no matter what you do. Even if you’ve decided you want to romance your fellow Dons and megalomaniacs like Byakuran.”

Yuni huffed cutely, pulling her arms away and stamping her foot. It still looked as cute as it had when she’d still been a child, sadly, being on the cusp of her twenties did nothing to detract from how cute she still was to him.

“Byakuran-chan isn’t a megalomaniac! Don’t be mean, Gamma!” she snapped, and Gamma’s lips quirked up in a wry grin.

“You sure about that, princess?” he drawled, and Yuni’s cheeks were touched with a pale pink as she flushed all the way to her ears.

“Maybe just a little bit,” she mumbled, and Gamma had to roll his eyes.

Well, at least she wasn’t deluding herself.

*

Gokudera, when Gamma showed up at his doorstep, broke out a bottle of scotch as soon as he was through the door and had kicked off his shoes, with respect for the Japanese custom that Gokudera seemed to be strictly following.

Gamma accepted the glass pushed into his hands, taking a sip and humming appreciatively before setting it down on the coffee table so he could shrug off his jacket, hanging it over the back of the couch. He then loosened his tie and rolled up his sleeves, and sank into the couch with a sigh of relief.

“I’m never going to get used to just how sultry it gets here,” he grumbled, and Gokudera laughed, settling down in the single couch on the other end of the table.

“That’s the both of us. Juudaime and Takeshi barely seem to notice – but then again, they grew up here.”

“We’re _Mediterranean._ The heat shouldn’t be messing with me so much.”

“Question not the weather and just be grateful for air conditioning,” Gokudera suggested, and Gamma lifted a toast to him in return.

“I’ll drink to that.”

It earned him a grin from the other man, Gokudera’s entire face lighting up with wry humor and making him look younger than the age his cigarette smoking habit had lent him.   

“Your Donna settle in okay? Byakuran and her cronies showed up yesterday night, they’re already at the mansion last I heard.”

“Yeah, I figured that out when I caught sight of Bluebell chatting with Sawada’s younger guardians,” Gamma sighed, sipping slowly at his drink. “Yuni shooed me off and insisted she would be fine before sitting down at the table with them.”

Gokudera laughed a little at that.

“Yeah, she gets along with Bluebell I think. Thankfully. It would have been messy if Bluebell had gotten jealous.”

“Like she is when it comes to Sawada?” Gamma asked amusedly, and Gokudera hid his grimace in his glass.

Gamma had been right. Gokudera _was_ easy company to spend time with, for all that they never really spent much time together unless they were with their charges.

They were suddenly interrupted when the front door swung open, Gamma immediately going for the gun in his shoulder holster and Gokudera’s hands bristling with dynamite. He groaned and made the sticks disappear again when he caught sight of who’d stepped into his apartment. On the other hand, Gamma’s eyes narrowed, and he made no move to lower his hand.

“Kikyou, you’ve got to stop doing that!” Gokudera snapped, knocking back the last of what was in his glass and immediately reaching out to pour himself some more, shaking his head in Gamma’s direction when he noticed that Gamma’s arm was still up.

“O-ho? Or what, little Hayato?” the tall, mint green haired man who’d stepped in asked, smiling sarcastically. He gave Gamma a little wave when he caught sight of him, laughing when Gamma grunted and went for his glass too.

“I just thought I should invite myself to your little gathering, seeing as you’re chatting about our bosses, right. I’m just going to go grab a glass for myself Hayato~” he trilled, sashaying off to what was presumably the kitchen.

Gamma raised his brows at Gokudera, who’d covered his eyes with his hands.

“Don’t ask. _Please_ don’t ask.” He hissed, before shoving himself to his feet.

“Kikyou, don’t you go rearranging my cupboards again damnit!”

Gamma stared after them, and silently reached for the bottle, pouring himself another finger as well. Apparently their bosses weren’t the only ones caught in a complicated relationship.

*

“Lord Byakuran has always cared for Yuni as well,” Kikyou remarked calmly, once he’d finished with Gokudera’s kitchen and had returned to pour himself a finger of scotch and settled down on the arm of Gokudera’s couch.

Gokudera, for his part, looked embarrassed and long-suffering, but he quietly sipped at his glass, not making any move to shove Byakuran’s right hand off of his perch.

“It isn’t a question of whether or not her fondness was _romantic._ For Lord Byakura, Tsunayoshi is Tsunayoshi, and Yuni is Yuni. The affection is the same, whether platonic or not. Pursuing either or was left fully in their hands.”

Gokudera snorted loudly, while Gamma lifted his fingers to his temple, massaging lightly.

“That doesn’t make sense at all,” he sighed, pained. Kikyou shot him a beautiful smirk, but he didn’t say anything, subsiding when Gokudera elbowed him pointedly.

“Makes sense to me,” Gokudera admittedly wryly. “Pretty sure her interaction with Juudaime went romantic as quickly as it did only because he was very obviously attracted to her even in the future.”

“Really?” Gamma asked incredulously, and wondered if she shouldn’t be warier of _Sawada_ than Byakuran.

Kikyou all but cackled, leaning into Gokudera comfortably and ignoring the curses it earned him with ease.

“Lord Byakuran mentioned that! Your Boss is the weird one, isn’t he Hayato?”

Gokudera made a face, and elbowed Kikyou pointedly before leaning back into his seat, frowning thoughtfully.

“He isn’t _weird._ He’s just clear on what he’s attracted to.”

“Princess and Byakuran are as different as night and day!” Gamma snapped, and earned himself a steady stare from both the other man.

“Oh? O-ho. I do believe the poor man actually _believes_ that, Hayato.” Kikyou said, lips tugging up in an unpleasant smile. Gamma might have protested if Gokudera hadn’t coughed awkwardly, making him shoot a betrayed glance at Sawada’s right hand.

Gokudera, for his part, simply lifted his hands up defensively, an awkward smirk stretched across his face.

“Your princess isn’t exactly _innocent,_ old man. She’s a whole lot like Byakuran when she wants to be. You’ve got to be able to see that.”

“Princess is Princess, and Byakuran is Byakuran,” Gamma replied waspishly, instead of actually responding to the statement, and knocked back the last of what was in his glass again, making both the other men laugh at him.

He had to smirk a little himself, honestly. Even if he didn’t really want to admit it, it was probably for the best that the people Yuni had chosen to pursue were clever enough to not be fooled by her innocently smiling face. Lies didn’t make for a healthy relationship. Gamma knew that better than anything else. He’d forgiven Aria plenty of things, he loved her too much not to, but he’d never forgiven her lies.

They spent the rest of the evening in easy conversation, Gamma trying to get used to the idea that this was going to become a more common occurrence if his Princess really did decide to take up with Sawada and Byakuran more permanently. At least he appeared to be in good company.

*

The first time he caught _Byakuran_ in bed with Yuni, he didn’t even hesitate to punt her right out the window.

Sawada and Yuni both stared after her, bemused, before turning their stares on Gamma. Gamma shrugged leisurely, turning a bland stare on Byakuran when she flew back up to climb through the windowsill.

“Was that really necessary,” she sighed. “We were just _talking.”_

“Apparently we’re supposed to be treating all parties of your relationship _equally._ It just wouldn’t be fair if you didn’t get the same treatment as Sawada, would it?” he offered, smiling beatifically.

“You were right,” Gamma heard Sawada whisper behind him. “He really _is_ like an overprotective dad.”

Gamma just smiled some more, and ignored the way Byakuran rolled her eyes, looking amused in spite of herself.

He doubted he would ever be comfortable with what Yuni had chosen for herself, but Gamma was willing to adjust if it would make Yuni happy. As long as both her suitors always knew that he would be around to keep an eye on them. It just wouldn’t do if they thought they could get away with hurting his Princess.

*

_“Y’know,” Tsuna mused, “I have to admit that it’s fun in its own way, knowing that at least one of us has an overprotective parent keeping an eye on us through this.”_

_Byakuran snorted, crossing one leg over the other and not moving her head from his stomach at all._

_“You’re just irritated he picked you to shove out of the window, Byakuran-chan,” Yuni giggled, her head resting on Byakuran’s stomach._

_“Can you blame me; there’s no way he didn’t do that on purpose,” Byakuran grumbled back, but her lips were tilted in a lazy little smile when she reached out to ruffle Yuni’s hair gently. Tsuna laughed, and reached out from where he was lying down so he could poke at Yuni’s curled up knees, making her squeak._

_This thing with Yuni was still brand new in a way his relationship with Byakuran simply wasn’t. They’d all been through hell and back together, and Yuni always had her little bit of fun teasing them both with what she could see in the future for them, but she’d never pushed her boundaries in their relationship until she was personally clear on what she wanted. And Tsuna and Byakuran had respected that, and had enjoyed her company because she was Yuni, and they’d been together for long enough, constantly meeting up when possible since the Representative Battles, whenever it was actually safe for Yuni to travel._

_They’d all grown possessive of each other, in their own way. Tsuna had known that Yuni would have to handle her Famiglia’s reaction to their relationship whenever it came to that point – but he hadn’t expected Gamma’s reaction at all. More the fool him._

_“Gamma doesn’t have to like you,” Yuni admitted, when she’d brought up the matter with him before he’d left Sicily earlier in the year. “He just has to know that_ I _like you. He’ll come to terms with it on his own if he knows I’m serious about this.”_

_“Makes sense, from what I remember of him,” Byakuran had admitted, a sharp smile tilting across her face. “He always did seem loyal to the point of blindness, that man.”_

_“It’s both a pro and a con, to be that blind to someone,” Yuni had declared carelessly. “But I know he loves me. And I love him for it. That’s all anyone really needs to be Family, right?”_

_Right. Tsuna and Byakuran had glanced at each other and both nodded at that. It was true, after all. Tsuna knew whom he belonged to. He always had. And Byakuran and Yuni belonged to him too. They were fine together, even if they confused anyone outside of their private circles._

_You didn’t need much more than loyalty and faith to be Famiglia. They all knew that down to their bones. Both in their larger Famiglia and in their little trio, together._

_They wouldn’t be torn apart no matter what Timoteo and Tsuna’s father wanted for him._

**Author's Note:**

> Hi there! Welcome to my Day Four/Lightning Day Entry for KHR Rare Pair Week. This is part of a larger series that's still being posted - I have one smutty interlude for it already up. The larger fic is still in the works, and is currently at 20k and counting. *grins wryly*
> 
> Hopefully this is going to be enjoyable even to those who're here just for love of the ship! I haven't seen too much Gamma and Yuni bonding, so here I am, offering parental fluff and OT3 love.
> 
>  **Kudos and Comments are very welcome!** I'm still responding to all the lovely comments I've received so far - I've been busy writing trying to keep to the Event Week deadlines. *smiles awkwardly* I'll get back to everyone though! And I'd love to hear what you have to say. Did you enjoy Gamma's chance at being an overprotective dad? How about his interaction with Yuni, and later with Gokudera and Kikyou?
> 
> The defenestration has been added for **[Seito](http://seitosokusha.tumblr.com)** , who is a wonderful enabler. XD
> 
> \---
> 
> For anyone interested, the next new AO3 post from me will be: Rain Day | Day Five's submission for KHR Rare Pair Week. If you've read Sky Day | Day Two, this is a prequel to that.
> 
> You can find me **[@adelmortescryche](https://adelmortescryche.tumblr.com)** \- come by and say hi! I don't bite.


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